CVE-2024-45403
When h2o is configured as a reverse proxy and HTTP/3 requests are cancelled by the client, h2o might crash due to an assertion failure.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.65%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. When h2o is configured as a reverse proxy and HTTP/3 requests are cancelled by the client, h2o might crash due to an assertion failure. The crash can be exploited by an attacker to mount a Denial-of-Service attack. By default, the h2o standalone server automatically restarts, minimizing the impact. However, HTTP requests that were served concurrently will still be disrupted. The vulnerability has been addressed in commit 1ed32b2. Users may disable the use of HTTP/3 to mitigate the issue.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.65% probability · 49th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-617
- Affected
- dena/h2o
- Source
- security-advisories@github.com
References
- https://github.com/h2o/h2o/commit/16b13eee8ad7895b4fe3fcbcabee53bd52782562Patch
- https://github.com/h2o/h2o/commit/1ed32b23f999acf0c5029f09c8525f93eb1d354cPatch
- https://github.com/h2o/h2o/security/advisories/GHSA-4xp5-3jhc-3m92Vendor Advisory
- https://h2o.examp1e.net/configure/http3_directives.htmlProduct
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.